1. Field of the invention
The present invention relates to a method for estimating the maximum power of a battery for a Hybrid Electric Vehicle (HEV), more particularly to an apparatus and a method for estimating the current maximum power of the battery by using the internal resistance of the battery, one of various environment parameters, which has the greatest effect on the maximum power of the battery mounted on a vehicle.
2. Description of the Prior Art
Electric vehicles use electric energy stored in a battery as an energy source. Lithium-ion polymer batteries are mainly used as the batteries for the electric vehicles, and researches for the lithium-ion polymer batteries have been progressed.
The power and the like of the battery mounted on the electric vehicle are controlled according to various control information stored in a Battery Management System (BMS). It is known that the estimation and the notification of the maximum power of the current battery, among the functions of the BMS, configure the most important information in the hybrid electric vehicle.
However, as the maximum power of the battery is sensitively changed according to temperature, the state of charge (SOC), and the state of health (SOH), it cannot be measured directly. Since the maximum power of the battery has too intensive a nonlinearity, it is impossible to measure the maximum power of the battery directly. Thus, only a method for estimating the maximum power of the battery indirectly has been proposed.
Nevertheless, a conventional art just discloses the method for estimating the maximum power of the battery only using the above-mentioned parameters such as temperature, the state of charge, and the state of health. It does not disclose a method for estimating the maximum power of the battery using the internal resistance of the battery, which directly relate to the maximum power of the battery.